News

Monday, August 24, 2015

Second Mares Conference Marine Ecosystems Health and Conservation February 1st to 5th 2016, Olhão, Portugal

The MARES Consortium and EuroMarine Network are pleased to invite you to participate in the second Mares Conference on Marine Ecosystems Health and Conservation.

The second Mares Conference will be held from 1st- 5th February, 2016 in Olhão, Portugal and is expected to attract around 200 attendees from across the world. It presents a unique opportunity to bring together marine researchers, scientists, educators and policymakers to address the key issues regarding marine ecosystems health and conservation. The conference will be dynamic and innovative, by providing a mixture of oral presentations, scientific exhibitions and training workshops. Throughout the conference scientific sessions and exhibitions the following six thematic subjects will be explored, with keynote speakers presenting on each theme:

  • Future oceans: temperature changes - hypoxia – acidification - Professor Jean-Pierre Gattuso
  • Understanding biodiversity effects on the functioning of marine ecosystems - Professor Steve Widdicombe
  • Biological invasions - Professor Anna Occhipinti Ambrogi
  • Natural resources: overexploitation, fisheries and aquaculture - Dr Jake Rice
  • Ocean noise pollution - René Dekeling
  • Habitat loss, urban development, coastal infrastructures and marine spatial planning - Dr Tundi Agardy

Further details regarding the conference venue, keynote speakers, scientific programme and training workshops are available on the Mares Conference webpage or visit the conference Facebook page. 

Thursday, March 26, 2015

Collaborations UGent – Québec

During a site visit in the harbor of Ghent (23 March 2015), we had the opportunity to meet with the Québec delegation (ambassador) in order to discuss future collaborations between Flanders and Québec, especially within the fields of marine and maritime sciences.

 

Were present at the meeting :

Michel Audet (Director General of Quebec in Brussels); Frédéric Tremblay (Dir. Bilateral affairs); Baudouin van Rijckevorsel (Economic Affairs), Stéphanie Franssen (Att. Bilateral Affairs), Aurélie Duchateau (DIV), Daan Schalck (ceo Havenbedrijf Gent), Dirk Vernaeve (havenkapitein-commandant), Peter Mortier (Adj. Directeur Generaal), Prof. Jan Mees (UGent – directeur VLIZ), Prof. E. Somers (UGent) en Prof. M. Vincx (UGent - voorzitter  marineatugent).

 

In case of interest with collaborations with Québec Universitities, Institutes, you can forward your questions to us or directly to Aurelie.duchateau@iv.vlaanderen.be.

At this moment there is an open call for collaborations within the framework of the FWO bilateral cooperation (http://www.fwo.be/en/news/calls/bilaterale-cooperation-quebec/). 

Friday, February 27, 2015

Gelatinous zooplankton in the Belgian part of the North Sea and the adjacent Schelde estuary: Spatio-temporal distribution patterns and population dynamics

Published paper: Gelatinous zooplankton in the Belgian part of the North Sea and the adjacent Schelde estuary: Spatio-temporal distribution patterns and population dynamics

 

Many ocean ecosystems are thought to be heading towards a dominance of gelatinous organisms. However, gelatinous zooplankton has been largely understudied and the absence of quantitative long-term data for the
studied area impedes drawing conclusions on potential increasing densities. This study gives a comprehensive overviewof the spatio-temporal distribution patterns of gelatinous zooplankton in terms of diversity and density
in the Belgian part of the North Sea and the adjacent Schelde estuary, based on monthly and seasonal samples between March 2011 and February 2012. Three Scyphozoa, three Ctenophora and 27 Hydrozoa taxa were iden-
tified, including three non-indigenous species: Mnemiopsis leidyi, Nemopsis bachei and Lovenella assimilis.In general, one gelatinous zooplankton assemblage was found across locations and seasons. Average gelatinous
zooplankton densities reached up to 18 ind·m−3 near the coast, gradually declining towards the open sea. In the brackish Schelde estuary, average densities remained below 3 ind·m−3
. Highest gelatinous zooplankton densities were recorded in summer and autumn. Overall, hydromedusae were the most important group both in terms of diversity and density. The ctenophore Pleurobrachia pileus and the hydromedusa Clytia sp. were present in every season and at every location. Gelatinous zooplankton densities never outnumbered the non-gelatinous zooplankton densities recorded fromtheWP3 samples. The spatial and temporal distribution patterns seemed to be mainly driven by temperature (season) and salinity (location). Other environmental parameters including (larger) non-gelatinous zooplankton densities (as an important food source) were not retained in the most parsimonious DistLM model.In terms of population dynamics, Beroe sp. seemed to follow the three reproductive cycles of its prey P. pileus and the presence of M. leidyi, which were abundant in a broad size spectrum in summer and autumn. In general, gelatinous zooplankton diversity was higher, but densities were in the same order of magnitude compared to adjacent areas in the North Sea. This study provides a baseline
against which a potential increase in gelatinous zooplankton in the Belgian part of the North Sea and the Schelde estuary can be measured.

 

Authors: Lies Vansteenbrugge, Tina Van Regenmortel , Marleen De Troch , Magda Vincx ,Kris Hostens

 

Read the article here: http://www.sciencedirect.com/science/article/pii/S1385110114002317 

Friday, February 27, 2015

Importance of reefs build by the polychaete worm Lanice conchilega

Recently, the news magazine Knack published an article (28/01/2015) on the importance of reefs build by the polychaete worm Lanice conchilega for the surrounding ecosystem. In Estuarine, Coastal and Shelf Science, Bart De Smet (Marine Biology Research Group) and colleagues provided more evidence on the key role of this bio-engineer for commercially important species such as shrimp and flatfish. You can find the article in Dutch here.

Wednesday, December 17, 2014

ir. Brecht Devolder wins 2 awards at the 15th FEA Research Symposium 2014

At the 15th edition of the FEA Research Symposium at Ghent University, Brecht Devolder was the winner of two awards (supervisors: Prof. Peter Troch and Prof. Pieter Rauwoens):

  • Poster Laureate selected by the Poster Award Committee.

  • Best poster Award presented by Doctoral Schools.

Abstract of Brecht Devolder

Wave energy from ocean waves is absorbed by using Wave Energy Converters (WECs). In order to extract a considerable amount of wave power at a location in a cost-effective way, large numbers of WECs are arranged in farms using a particular geometrical configuration. Interactions between the individual WECs (near field effects) affect the overall power production of the farm. One should avoid, for instance, that one WEC is positioned in the wake region of another WEC. The wave height reduction behind an entire WEC farm (far field effects) affects other users in the sea, the environment or even the coastline. 
By using a coupled numerical modeling, we aim to develop a methodology (and a related numerical tool) to answer the fundamental underlying questions on farm design: finding the optimal and cost-effective configurations of WEC farms for power production, and quantifying the related environmental impact. A numerical model, suited for near field effects will be developed and validated. It will be combined with a numerical model suited for predicting far field effects for two purposes: to reduce the computational cost of the near field model and to get more accurate results of the far field effect of WECs.

Monday, December 15, 2014

Members of ‘Coastal Engineering’ editorial board

Prof. Peter Troch and Prof. Andreas Kortenhaus, both researchers in the field of coastal structures at the Department of Civil Engineering at Ghent University, have joined the editorial board of the leading international journal, 'Coastal Engineering'. 

 

The board consists of a selected range of international specialists from renowned universities and water institutes such as Deltares, HR Wallingford and DHI.

Monday, December 15, 2014

Characterising the middle Miocene Mi-events in the Eastern North Atlantic realm

Published paper: Characterising the middle Miocene Mi-events in the Eastern North Atlantic realm: A first high-resolution marine palynological record from the Porcupine Basin

 

The warm climate of the Miocene peaked during the middle Miocene Climatic Optimum (MMCO; 17–14.5 Ma). After the MMCO, global climate went through several short-lived cooling events: the Mi-events (Miocene isotope events). One of the more severe Mi-events is Mi-3, associated with East Antarctic Ice Sheet growth, species turnover in terrestrial and marine realms, Northern Hemisphere and mid-latitude aridification and Antarctic sea-surface temperature cooling. CO2 reconstructions, as well as the aforementioned observations, suggest that a drawdown of CO2 and/or changes in ocean circulation led to the changes surrounding Mi-3. A combination of eccentricity and obliquity amplitude modulation minima, favourable conditions for ice growth, has also been suggested as a possible triggering mechanism. However, an exact cause cannot be pinpointed yet. High-resolution records necessary to investigate the exact order of events surrounding Mi-3 and the possible role of orbital forcing, a very likely trigger, are sparse. Integrated Ocean Drilling Program (IODP) Leg 307 recovered such a high resolution record from the middle Miocene at the Porcupine Basin (offshore south-western Ireland). Well-preserved palynomorphs, mainly organic-walled dinoflagellate cysts, acritarchs and some pollen were extracted from Site U1318, and relative and absolute abundance changes were determined. Using dinocysts and calcareous nannoplankton the age model for the record was improved. Based on the palynology, the Mi-3a, Mi-3b and Mi-4 events were successfully identified and concomitant palaeoenvironmental change was observed. These events, although different in magnitude, can be associated with a decrease in sea-surface temperature, as well as with a likely fall in sea-level. Furthermore, possible palaeoenvironmental preferences of 5 dinocyst taxa were determined, based on observations from the record and multivariate statistics.

 

Authors: Willemijn Quaijtaal, Timme H. Donders, Davide Persico, Stephen Louwye

 

Read the paper here

Picture: Operculodinium

Thursday, December 11, 2014

Norepinephrine and dopamine increase motility, biofilm formation, and virulence of Vibrio harveyi

Published paper: Norepinephrine and dopamine increase motility, biofilm formation, and virulence of Vibrio harveyi

 

Vibrio harveyi is one of the major pathogens of aquatic organisms, affecting both vertebrates and invertebrates, and causes important losses in the aquaculture industry. In order to develop novel methods to control disease caused by this pathogen, we need to obtain a better understanding of pathogenicity mechanisms. Sensing of catecholamines (stress hormones produced by higher organisms) increases both growth and production of virulence-related factors in pathogens of terrestrial animals and humans. However, at this moment, knowledge on the impact of catecholamines on the virulence of pathogens of aquatic organisms is lacking. In the present study, we report that in V. harveyi, norepinephrine (NE) and dopamine (Dopa) increased growth in serum-supplemented medium, siderophore production, swimming motility, and expression of genes involved in flagellar motility, biofilm formation, and exopolysaccharide production. Consistent with this, pretreatment of V. harveyi with catecholamines prior to inoculation into the rearing water resulted in significantly decreased survival of gnotobiotic brine shrimp larvae, when compared to larvae challenged with untreated V. harveyi. Further, NE-induced effects could be neutralized by α-adrenergic antagonists or by the bacterial catecholamine receptor antagonist LED209, but not by β-adrenergic or dopaminergic antagonists. Dopa-induced effects could be neutralized by dopaminergic antagonists or LED209, but not by adrenergic antagonists. 

 

Together, our results indicate that catecholamine sensing increases the success of transmission of V. harveyi and that interfering with catecholamine sensing might be an interesting strategy to control vibriosis in aquaculture. We hypothesize that upon tissue and/or hemocyte damage during infection, pathogens come into contact with elevated catecholamine levels, and that this stimulates the expression of virulence factors that are required to colonize a new host.

 

Authors: Qian Yang, Nguyen D. Q. Anh, Peter Bossier and Tom Defoirdt

 

Read the paper here

Tuesday, December 9, 2014

Protocol for quantitative shape analysis of deformities in early larval European seabass Dicentrarchus labrax

Published paper: Protocol for quantitative shape analysis of deformities in early larval European seabass Dicentrarchus labrax

 

This study established an optimized protocol for quantifying the shape variation of newly hatched larvae of European seabass Dicentrarchus labrax, focusing on the effect of fixatives and mounting on body shape from hatching until 14 days post hatching, while also minimizing the error introduced by handling. This assessment was performed based on both biometric and geometric shape data, with the latter relying on outline based elliptic Fourier analysis. The fixation and mounting effect on the total length and shape of newly hatched larvae of D. labrax was tested for four fixation treatments: (1) 8% formalin, (2) 70% ethanol, (3) 8% formalin for 48 h and then to 70% ethanol and (4) 3% phosphate-buffered glutaraldehyde. The analyses showed that no significant size and shape effect was observed on anaesthetized specimens 5 months post-fixation in glutaraldehyde, and that the glycerol mounting process of specimens fixed in glutaraldehyde provided the best results for further ontogenetic qualitative and quantitative analysis. The protocol proved to be sufficiently sensitive to even quantify and visualize subtle pre-fixation shape differences originating from a different egg batch.

 

Authors: S. Nikolakakis, P. Bossier, G. Kanlis, K. Dierckens and D. Adriaens

 

Read the paper here

 

Pictures: 

(1) Seabass larva, 14 days after hatching. Stained with alizarin red. The dark line that appears is the start of the formation of the pectoral girdle and the cleithrum bone which will later support the pectoral fins.

(2) Seabass larva, 7 days after hatching. 

 

Friday, December 5, 2014

The link between meiofauna and surface productivity in the Southern Ocean

Published paper: The link between meiofauna and surface productivity in the Southern Ocean

 

Particulate organic carbon (POC) export fluxes generally reflect patterns of primary production in the upper ocean, sinking to the seabed and acting as a food source for benthic organisms. Data on meiobenthic communities from two SYSTem Coupling cruises (SYSTCO) in the deep Southern Ocean (RV Polarstern ANT-XXIV/2, north–south transect along the prime meridian, and ANT-XXVIII/3, east–west transect along the Polar Front) were combined with surface and benthic environmental parameters, as well as POC flux estimates based on satellite measurements. It was tested to what extent meiofaunal communities were determined by prevailing conditions of an east–west increase in net primary productivity (NPP) and bottom Chlorophyll a (Chla) concentration, and a westwards, divergently decreasing estimated POC flux. Nematodes dominated the meiofauna (84.4–92.4%) and occurred with a westward increase in relative abundance and density for the ANT-XXVIII/3stations, associated with a parallel increase in NPP and Chla. Nematode biomass was negatively correlated to the estimated POC flux. Along the north–south transect no significant correlation was found but higher estimated POC fluxes at stations south of the Polar Front were associated with higher meiofauna diversity and density at higher taxon level, while stations located at the Polar Front, which were associated with lower POC fluxes, contained communities with lower diversity and density.

 

Read the paper here

 

Authors: L. Lins, K. Guilini, G. Veit-Köhler, F. Hauquier, R. M. S. Alves, A. M. Esteves, A. Vanreusel

Wednesday, December 3, 2014

Antarctic shallow water benthos in an area of recent rapid glacier retreat

Published paper: Antarctic shallow water benthos in an area of recent rapid glacier retreat

 

The West Antarctic Peninsula is one of the fastest warming regions on Earth. Faster glacier retreat and related calving events lead to more frequent iceberg scouring, fresh water input and higher sediment loads, which in turn affect shallow water benthic marine assemblages in coastal regions. In addition, ice retreat creates new benthic substrates for colonization.

 

We investigated three size classes of benthic biota (microbenthos, meiofauna and macrofauna) at three sites in Potter Cove (King George Island, West Antarctic Peninsula) situated at similar water depths but experiencing different disturbance regimes related to glacier retreat. Our results revealed the presence of a patchy distribution of highly divergent benthic assemblages within a relatively small area (about 1 km2). In areas with frequent ice scouring and higher sediment accumulation rates, an assemblage mainly dominated by macrobenthic scavengers (such as the polychaete Barrukia cristata), vagile organisms and younger individuals of sessile species (such as the bivalve Yoldia eightsi) was found. Macrofauna were low in abundance and very patchily distributed in recently ice-free areas close to the glacier, whereas the pioneer nematode genus Microlaimus reached a higher relative abundance in these newly exposed sites. The most diverse and abundant macrofaunal assemblage was found in areas most remote from recent glacier influence. By contrast, the meiofauna showed relatively low densities in these areas. The three benthic size classes appeared to respond in different ways to disturbances likely related to ice retreat, suggesting that the capacity to adapt and colonize habitats is dependent on both body size and specific life traits. We predict that, under continued deglaciation, more diverse, but less patchy, benthic assemblages will become established in areas out of reach of glacier-related disturbance. 

 

Read the paper here.

 

Authors: Francesca Pasotti, Elena Manini, Donato Giovannelli, Anne-Cathrin Wölfl, Donata Monien, Elie Verleyen, Ulrike Braeckman, Doris Abele & Ann Vanreusel

Friday, November 28, 2014

Biogenic reefs affect multiple components of intertidal soft-bottom benthic assemblages: the Lanice conchilega case study

Published paper: Biogenic reefs affect multiple components of intertidal soft-bottom benthic assemblages: the Lanice conchilega case study

 

Biogenic reefs composed of the tube-building polychaete Lanice conchilega are important from a conservation point of view because they noticeably increase the biodiversity in otherwise species poor environments. However, up to now, little or no attention has been paid to the intertidal epi- and hyperbenthic communities associated with the reefs. Therefore, this is the first study which focuses on the effect of L. conchilega reefs on the entire bentho-pelagic community at two different locations. Environmental variables were measured and macro-, epi- and hyperbenthic communities were sampled within a L. conchilega reef and a control area at two locations in France: the bay of the Mont Saint-Michel (BMSM) and Boulogne-sur-Mer (Boulogne). The effect of the reef presence on the benthic community was studied with a 3-factor (Reef, Location and Period) Permanova. In addition, the relationship between the benthic community and the environmental variables was investigated using Distance-based linear models (DistLM). Most collected organisms were sampled in the reef area (macrobenthos: 91%, epibenthos: 81% and hyperbenthos: 78.5%) indicating that, independent of the location, the L. conchilega reefs positively affect all three associated benthic communities. However, the extent of the effect seems to be most pronounced for the macrobenthos and less distinct in case of the hyperbenthos. The macro-, and epibenthos are mainly structured by biotic variables (L. conchilega density and macrobenthic food availability respectively), while the hyperbenthos is rather structured by environmental variables. In general, L. conchilega reefs do not only affect abundances and diversity but they substantially steer the structure of the intertidal benthic sandy beach ecosystem.

 

Authors: Bart De Smet, An-Sofie D'Hondt, Pieterjan Verhelst, Jérôme Fournier, Laurent Godet, Nicolas Desroy, Marijn Rabaut, Magda Vincx, Jan Vanaverbeke

 

Read the paper here

Tuesday, November 18, 2014

Outreach matters!

Marine@UGent scientists believe that outreach matters. That is why we are involved in several outreach projects! 4 projects this week: 

 

The 'Smaakboot' is a historic ship that makes a culinary journey between two anchor cities on a daily basis between 13 and 23 November. The 40 passengers who won a ticket, enjoy a three-coarse lunch with Belgian fish. A top chef prepares this delicious menu, and scientists and fishermen tell passengers something about sustainable fish and fishing. Our scientists will talk about sustainable fish on 20, 22 and 23 November. Read all about it on http://www.smaakboot.be/ (in Dutch). 

Every day you can win the last tickets on Facebook: www.facebook.com/WeekVanDeSmaak

 

 

 

 

Biologists will be present on the science festival in the Vooruit, Ghent (Sunday 23 November), where they will have a stand focussed on aquaculture. How much do you know about aquaculture? Is 5 kg fish required to grow 1 kg of salmon? Is farmed fish full of antibiotics? Does aquaculture have a detrimental impact on the environment? Is pangasius farmed under unhealthy conditions, in a dirty pond? Come and find out!

Do you taste the difference between wild and farmed sea bass? Which do you prefer? Our scientists will let you taste. Read more on http://www.waarofnietwaar.be (in Dutch).

When? Sunday 23 November, 13-17u (science festival). Where? Vooruit, Sint-Pietersnieuwstraat 23, Ghent. Free! 

 

 

 

Also on Sunday 23 November, biologists will play games with kids (age: 9-12) to learn them something about sustainable fish. This is organized for the 'Week of Taste' (Week van de Smaak) and will take place in Eetcafé Toreke in Ghent. Read more about it here (in Dutch). While the kids are playing, parent can taste fish and chips! 

When? Sunday 23 November, 16-17h, 17h30-18h30, 19-20h. Where? Eetcafé Toreke, Vlotstraat 22, Ghent. Free!

 

 

 

 

 

 

 

Visit - for the very first time! - the Marine Station in Ostend from the Flanders Marine Institute on Sunday 23 November. For the 'Day of science', you can: 

- dive virtually to the deep sea with the underwater robot Genesis

- discover the microscopic life in a drop of seawater

- discover the most eccentric animals in the Curiosity Cabinet ... And much more! 

When? Sunday 23 November, 10-17h. Where? Slipwaykaai 2, Ostend.

Read more (in Dutch). 

 

Tuesday, November 18, 2014

NeMys – the World Database of Free-Living Marine Nematodes – has joined forces with WoRMS

WoRMS and the online nematode biodiversity information system NeMys have joined forces. Early 2014, it was decided to transfer the World Database of Free-Living Marine Nematodes (NeMys) from its original host institute – the Marine Biology Section at Ghent University (MarBIOL) – to the Flanders Marine Institute (VLIZ), the host institute of the World Register of Marine Species (WoRMS). NeMys is now fully integrated into WoRMS and it has kept all its functionalities as in the previous stand-alone version at Ghent. As NeMys is now part of WoRMS, all changes made in NeMys will automatically be visible within WoRMS.

 

NeMys focuses on the taxonomy of the free-living marine nematodes. In addition, NeMys holds 11 identification keys,  to identify nematode specimens to their genus level. Some ID-keys to species level are included as well. Registered users have full access to the available taxonomical literature, either through PDFs of entire papers, or as snippets of the relevant information from the literature. This easy access to literature is a major advantage, as the original species descriptions are needed to correctly identify nematodes to species level. As such, NeMys – and thus WoRMS - are opening the taxonomical literature on Nematodes to all interested taxonomists and ecologists.

 

Since NeMys and WoRMS have joined forces, a new editorial team for free-living marine nematodes has been installed. The editorial team currently consists of 10 members, covering a large geographical area and a broad taxonomical expertise. Early next year, these taxonomic experts will meet at the Flanders Marine Institute for a 2-3 day workshop, where they will get familiar with WoRMS and its online editing interface and discuss the way forward for NeMys.

Picture by Freija Hauquier. 

 

URL: http://nemys.ugent.be/

 

Tuesday, November 18, 2014

De smaaktest!

Proef je het verschil tussen wilde en gekweekte vis? Wat denk jij? 

Wat is lekkerder? Wilde of gekweekte vis? 

 

Doe de test bij onze wetenschappers op het wetenschapsfestival in de Vooruit op zondag 23 november tussen 13 en 17u. 

Vul even deze 2 vragen in en proef dan blind onze zeebaars. 

 

Monday, November 17, 2014

Academy award for science outreach: first laureate

Professor Magda Vincx has been awarded by the Royal Flemish Academy of Belgium for Science and the Arts for two outreach projects: Marine Art and the Sustainable Fish Week. She was one of 12 laureates. The 12 winners were honored at a science communication event last Wednesday, 28 November, where the first, second and third award were also annouced. 

 

Magda Vincx, together with the Marine@UGent consortium, received the first award for 'exceptional achievements of researchers in science communication'. The second award went to Ann Dooms, the third award to the team behind the blog mensenkennis. This is great news for all participants of Marine Art and the Sustainable Fish Week: all researchers, art teachers, and art students. And this is certainly an incentive to start with or continue with outreach projects. 

 

Read more about it on the website of the KVAB.

 

 

 

 

Tuesday, November 11, 2014

First 'Communication in Marine Sciences' event

On 28 October, Marine@UGent organized the first 'Communication in Marine Sciences' event for young scientists. 30 enthuasiastic scientists were present, eager to learn how to communicate more effectively.

 

To initiate the day, professor Magda Vincx introduced Marine@UGent to them. Then, 3 keynote speakers shed their light on science communication, from their respective perspectives. Jos Van Hemelrijck elaborated on why scientists should talk to journalists and more importantly, how to talk to journalists. Stephanie Lenoir explained the role of the Communications Office. Professor Katrien Strubbe also explained why and how researchers should communicate their science, from her perspective as a scientist with ample experience with outreach projects. After the keynote speaches, it was time to get to know each other (a bit better): Sylvie Peeters from the Communication department organized a speeddating event (see picture). Researchers met colleagues from other research groups and perhaps new collaborations were initiated. After lunch, three workshops took place: Social media by Ineke Imbo, Sharing marine science with the public by Jan Seys, and Effective scientific posters by Ruben Verborgh. Comments from the participants were extremely positive, apparently, these workshops can be highly recommended! A must for next year's participants perhaps! Did you miss the event, have a look at the presentations: 

 

Magda Vincx - Presentation Marine@UGent

Jos Van Hemelrijck - Talking to the press

Stephanie Lenoir - Role of the Communications office

Katrien Strubbe - Science for all or how do/can we communicate science?

Ineke Imbo - Social Media

Jan Seys - Sharing Marine Science with the Public

Unfortunately, the slides of Ruben Verborgh (Effective scientific posters) are not available. 

Monday, November 10, 2014

Diseased seahorses: white necrotic tail tips in estuary seahorses

Seahorses are classified as threatened species. They are popular in global aquarium trade but in captivity, they are very susceptible to parasitic, fungal and bacterial ailments. White discolouration of the tail is a frequently occurring phenomenon, well-known amongst seahorse keepers, but still with an unclear origin. 

 

Seven seahorses displaying white necrotic tails transforming into white patches covering the distal part of the tail, were brought to the Faculty of Veterinary Medicine at Ghent University. Early observations in the disease stadium were agitated swimming behaviour, scraping with the tail and an increased breathing ratio. Gradually, the soft tissue of the distal part of the tail disappeared and in some cases led to the exposure of the vertebral column, resulting in the death of the animal.

 

Protozoans were observed on the skin samples with a morphology resembling that of species belonging to the genus Uronema (Scuticociliatida). Scuticociliates may become opportunistic histophagous parasites causing severe infections in marine fish, crustaceans and molluscs. The presence of these ciliates in fish tissues has been associated with pathological signs, including skin ulcers spreading into muscular tissue and even exposing the fin rays. Massive clusters of bacterial cells, exhibiting the same morphology as Tenacibaculum aestuarii, were observed invading the subcutaneous tissue. This Tenacibaculum species has never before been associated with neither disease signs nor mortality, however, various members belonging to the family Flavobacteriaceae are notorious pathogens in the aquaculture industry and the ornamental fish sector.

 

Additional studies are required to rectify or dismantle the above hypothesis that both scuticociliatosis and Tenacibaculum rank amongst the causative agents of white tail disease.

 

Published paper (Short communication), read it here. Authors: A.M. Declercq, K. Chiers, W. Van den Broeck, A. Rekecki, S. Teerlinck, D. Adriaens, F. Haesebrouck and A. Decostere.

Thursday, November 6, 2014

TONIGHT: Science Cafe: Urban legends in aquaculture

The third edition of the Sustainable Fish Week takes place between 3 and 7 November at Ghent University. The focus is on 'urban legends in aquaculture'. How much do you know about aquaculture? Is 5 kg fish required to grow 1 kg of salmon? Is farmed fish full of antibiotics? Does aquaculture have a detrimental impact on the environment? Is pangasius farmed under unhealthy conditions, in a dirty pond? Discuss with our experts in our Science Cafe! 

 

Location: Herberg Macharius, Voorhoutkaai 43+, Ghent

When? Thursday 6 November, 19h 

 

Confirmed speakers:

Moderator Jan Seys, Flanders Marine Institute 

Professor Peter Bossier, Aquaculture and Artemia Reference Center, Ghent University 

Franck Hollander, WWF

Arne Goyvaerts, Sea First Foundation

Thursday, November 6, 2014

Strong underwater sound waves not lethal for noise-sensitive species (young sea bass)

Unique experimental field research in marine Belgian wind farm shows: strong underwater sound waves not lethal for noise-sensitive species (young sea bass)

 

Impact assessments of offshore wind farm installations and operations on the marine fauna are performed in many countries. Yet, only limited quantitative data on the physiological impact of impulsive sounds on (juvenile) fishes during pile driving of offshore wind farm foundations are available. Our current knowledge on fish injury and mortality due to pile driving is mainly based on laboratory experiments, in which high-intensity pile driving sounds are generated inside acoustic chambers. To validate these lab results, an in situ field experiment was carried out on board of a pile driving vessel. Juvenile European sea bass (Dicentrarchus labrax) of 68 and 115 days post hatching were exposed to pile-driving sounds as close as 45 m from the actual pile driving activity. Fish were exposed to strikes with a sound exposure level between 181 and 188 dB re 1 µPa².s. The number of strikes ranged from 1739 to 3067, resulting in a cumulative sound exposure level between 215 and 222 dB re 1 µPa².s. Control treatments consisted of fish not exposed to pile driving sounds. No differences in immediate mortality were found between exposed and control fish groups. Also no differences were noted in the delayed mortality up to 14 days after exposure between both groups. Our in situ experiments largely confirm the mortality results of the lab experiments found in other studies.

 

You can read the paper here. Authors: Elisabeth Debusschere, Bert De Coensel, Aline Bajek, Dick Botteldooren, Kris Hostens, Jan Vanaverbeke, Sofie Vandendriessche, Karl Van Ginderdeuren, Magda Vincx, Steven Degraer. 

 

The Dutch press release can be found here

Picture copyright: Karl Van Ginderdeuren. 

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